Regional heating by insertion of dielectrics and rotation of the focused electric field in the hyperthermia

We have developed a cancer treatment system that utilizes a reentrant resonant cavity to heat the localized deep lesion inside the living body non-invasively. In this study we focused the electric field distribution by loading a dielectric between the reentrant electrodes and an object, and attempted to optimize the shape and the size of the loaded dielectric. The basic experiment using prototype equipment and numerical analysis using the three-dimensional finite element method indicated that we can improve the focusing effect of 10–20 % compared with our previous heating system by the loaded dielectric. In addition, we confirmed that the focusing effect of the electric field distribution can be achieved by rotating the applicator in order to accurately heat a small localized region of 30–50 mm in diameter.